This invention relates to a turning tool having a cutting tip attached to the front end thereof.
Turning tools are known where the cutting tip is permanently attached to the front end of a shank of the tool body, e.g., by brazing. In by far the most cases, however, the cutting tip is detachably fixed to the front end of the shank so that it may be successively used in different positions as a so-called reversible cutting tip.
Cutting tips are to be found on the market which differ from one another in their shape (e.g., rhombic, triangular, etc.) and/or in their cutting angle. On the shanks or tool bodies, not only must the front part be prepared so that it can receive a cutting tip of a particular type to be fixed permanently or detachably, but in a first group of tools, this front part must extend straight out in the line of prolongation of the shank, while in another group of tools, the central plane of the front part must form an angle of between 90.degree. and 180.degree. with the central plane of the shank in order for the tools to be suitable for different turning operations and/or so that a tool with a "right-handed head" or a "left-handed head" may be obtained.
It follows from these requirements that not only the manufacturers of such tools but also the wholesalers are obliged to produce and stock, respectively, an enormous number of the most varied tools, some of which are very much in demand, while others are not much in demand. The storage costs are naturally added to the cost of manufacture.
It has therefore been sought to design a turning tool in such a way that the costs of manufacture and storage can be reduced by making it more efficient. U.S. Pat. No. 3,500,523 teaches a tool holder in which a tool bit is held in a correspondingly shaped recess of a carrier. The carrier, the tool bit, and the parts serving to clamp the tool bit to the carrier rest on the front end of the tool holder body in a suitably shaped recess thereof. The plate-like carrier rests on the base of this latter recess and has at its rear an arcuate, inclined wall which may be brazed at each end to a matching wall of the recess. A pin, coaxial with the aforementioned acruate, inclined surfaces and secured to the body, is provided as a pivot for the carrier prior to its being brazed to the body. Although this patent proposes the manufacture in large groups, of identical bodies and identical carrier parts, i.e., assemblies comprising a carrier, tool bit, and associated clamping means propose the fitting of each such assembly in rotatingly adjustable orientation on the base of the recess in the body, and finally its fixing to the body by spots of brazing an expedient rotating adjustment cannot actually take place to any significant extent with the design shown. The more the carrier is rotated out of the position in which it occupies the recess in the body completely, as viewed from above, the more it will project out of its recess to one side or the other of the body. This will have an unfavorable weakening effect in several respects. There will be increasingly less contact surface between the carrier and the base of the body recess, eccentricity of the application of force, and increasingly less place, or finally none at all, for spots of brazing on the projecting portion. With respect to the relative positions of the tool and the workpiece, too, impossible conditions may be brought about where the body would come into conflict with the workpiece.
The prior art also includes the turning tool taught by German Published Application No. 1,294,781. There an insert part comprising a cutting insert is brazed or soldered along slanting up towards the front and down towards the front to the front end of the tool shaft; one or both of these surfaces are provided with shims so that the cutting insert, when detached from the tool shank, can be brought back into its previous position after the regrinding of the top and front faces. This disclosure, however, teaches nothing which contributes toward alleviating the aforementioned drawbacks of the prior art.